Question | Answer |
Apical Ectodermal Ridge (AER | stimulate extension of limbs
CC:Remove AER leads to limb defects
Thalidomide inhibits proliferation and interupts the AER functioning |
FGFR-3 | Lengthening of limbs
CC: Disruption leads to dwarfism |
HOX | Segmentation - Provides address for limbs CC: Results from failure of webs to degenerate (ie failure of cell death/apoptosis).
Limbs in wrong places
Klippel-Feil
Brevicollis
Syndactyly |
WNT7a | Organization along Dorsal-Ventral axis |
ZPA | Morphogenic control region located at the base of the developing limb bud. Regulates differentiation of digits. |
MyoD | Induces muscle development
CC: Prune Belly, Congenital Torticollis, Poland Syndrome |
PAX6 | Patterning of neural tube Basal - Primary
Motor-efferent |
SHH | patterning along anterior-posterior axis |
PAX3 | Patterning of neural tube Alar-sensory- afferent |
Joint formation | Type depends on extracellular matrix secreted |
Synovial joint | Central mesenchyme disappears to form cavity (depends on movement)
(diarthrosis) - freely moveable joints are the most common found |
Fibrous joint | like sutures of the skull
synarthrodial - immoveable joints found in cranial vault and teeth |
Cartilaginous joint | Hyaline or fibrocartilage formed; synchondroses and sympheses - partially moveable joints
Ex: costochondral joints, pubic symphysis |
Joint movement - hinge | Flexion/Extension; elbow/knee |
Joint movement - pivot | Rotation of one bone around another; neck, atlas and axis bones |
Joint movement - ball and socket | shoulder and hip |
Joint movement - saddle | thumb |
Joint movement - condyloid | Wrist joints |
Joint movement - Gliding | Gliding movements; intercarpal joints |